Numerous reports of anaphylactoid reaction to d-tubocurarine have appeared since 1936. Also it has been suggested that histamine released as a consequence of clinical doses of d-tubocur arine is not in sufficient quantity to evoke symptoms. We recently had experience with a case who had of severe circulatory collapse and urticarial reaction while being anesthetized with ether and d-tubocurarine. This report draws attention to the risk of administering histamine releasing drugs and references are reviewed.